The UK-PBC Risk Scores: Derivation and validation of a scoring system for long-term prediction of end-stage liver disease in primary biliary cirrhosis

BACKGROUND: The biochemical response to ursodeoxycholic acid (UDCA) - so-called 'treatment response' - strongly predicts long-term outcome in primary biliary cirrhosis (PBC). Several long-term prognostic models based solely on the treatment response have been developed that are widely used to risk-stratify PBC patients and guide their management. However, they do not take other prognostic variables into account, such as the stage of the liver disease. We sought to improve existing long-term prognostic models of PBC using data from the UK-PBC Research Cohort.

METHODS: We performed Cox proportional hazards regression analysis of diverse explanatory variables in a derivation cohort of 1,916 UDCA-treated participants. We used non-automatic backward selection to derive the best-fitting Cox model, from which we derived a multivariable fractional polynomial (MFP) model. We combined linear predictors and baseline survivor functions in equations to score the risk of a liver transplant or liver-related death occurring within 5, 10 or 15 years. We validated these risk scores in an independent cohort of 1,249 UDCA-treated participants.

RESULTS: The best-fitting model consisted of the baseline albumin and platelet count, as well as the bilirubin, transaminases and alkaline phosphatase after 12 months of UDCA. In the validation cohort, the 5, 10 and 15-year risk scores were highly accurate (AUCs > 0.90).

CONCLUSIONS: The prognosis of PBC patients can be accurately evaluated using the UK-PBC risk scores. They may be used to identify high-risk patients for closer monitoring and second-line therapies, as well as low-risk patients who could potentially be followed-up in primary care. This article is protected by copyright. All rights reserved.